Medical and surgical procedures using optical energy or light, such as laser energy, have been developed for a wide range of treatments. Historically, light was delivered to tissue to be treated in a direct line from the light source to the tissue by travelling through air. Subsequently, articulated arms, hollow wave guides, and fiber optics have provided more flexible and clinically suitable ways of delivering optical energy to tissue, but the energy still travelled through air before reaching the tissue. Delivery systems of this type are frequently referred to as non-contact delivery systems, since the delivery system is not intended to contact tissue in order to deliver energy to it. Although useful in many applications, non-contact delivery systems suffer from several drawbacks.
To overcome the drawbacks of non-contact delivery systems, numerous devices and techniques have been developed that permit direct contact between the delivery system and tissue, although both contact and non-contact delivery systems are used.
In recent years, attention has been given to the treatment of cutaneous tissue by optical energy. For example, U.S. Pat. No. 5,282,797 to Chess teaches a non-contact device and method for treating cutaneous vascular lesions by passing a laser beam through a cooling medium on its way to a patient's epidermis. The cooling medium is used to cool the patient's epidermis while it is being exposed to the laser beam. The need for a secondary device, such as a container to hold a cooling medium, separate from the laser delivery system makes the Chess apparatus and technique cumbersome. The coolant container must be frequently changed, since it will reach or exceed body temperature in a short time and become ineffective. The placement of a separate container between the delivery system and the tissue prevents tactile feedback to the surgeon manipulating the delivery system, and prevents the tissue from being compressed. It also alters the laser beam diameter and thus its power density.
U.S. Pat. No. 5,057,104, also to Chess, eliminates the coolant container and subjects the patient's epidermis to a cooling fluid. However, this patent also illustrates a non-contact device, i.e., there is no contact between the delivery system and the tissue, and thus it suffers from the same drawbacks as the device previously described. Moreover, as with all non-contact devices, it is difficult to keep the distance to tissue a constant and therefore the beam diameter, and thus power density, can change substantially.
U.S. Pat. No. 5,595,568 to Anderson, et al., discloses a method and apparatus for removing multiple hair follicles from skin. The method involves eliminating the hairs and follicles with optical energy delivered by a transparent tissue contact device. The apparatus includes an optically transparent contact device having a surface shaped to simultaneously contact several hair follicles in a region of the skin, and for delivering optical energy to a region of the skin, including the hairs and hair follicles. While the contact surface of the contact device is convex, sliding friction between the contact device and the surface of the skin can be problematic. The contact device is cooled by passing a cooling fluid over the rear surface of the contact device, i.e., the surface which does not contact the patient's skin. This is said to indirectly cool the patient's skin, but no direct cooling of the skin by a cooling fluid takes place.
U.S. Pat. No. 5,611,795 to Slatkine discloses a method of facial rejuvenation by using a carbon dioxide laser in conjunction with a flash scanner to ablate, or remove, an area of facial skin above the papillary dermis. There is no disclosure of any contact between the apparatus and the facial skin, which is consistent with the use of a carbon dioxide laser.
The present invention is intended to eliminate the drawbacks of the prior apparatus and methods. It is an object of the present invention to provide an effective apparatus and method to deliver sub-surface irradiation of tissue while providing the surgeon a greater degree of control over clinical effect. Another object of the invention is to provide tissue compression to give the surgeon the greater degree of control over the clinical effect obtained.
It is another object of the invention to provide subsurface irradiation of tissue with minimal surface temperature effects.
Another object of the invention is to provide an apparatus and method that provides direct cooling of the surface tissue while providing subsurface irradiation.
Yet another object of the invention is to provide low friction movement of the treatment apparatus over the tissue surface.